Sorry for the spam, b4 and smtp with google are not playing nice and failed (but worked fine with --reflect). I'll send a v3 the old school way. My apologies, Andrew On Thu, Dec 21, 2023 at 12:25:17PM -0600, Andrew Halaney wrote: > This is an RFC because I'm not all the confident in this topic. UFS has > a lot of mb() variants used, most with comments saying "ensure this > takes effect before continuing". mb()'s aren't really the way to > guarantee that, a read back is the best method. > > Some of these though I think could go a step further and remove the mb() > variant without a read back. As far as I can tell there's no real reason > to ensure it takes effect in most cases (there's no delay() or anything > afterwards, and eventually another readl()/writel() happens which is by > definition ordered). > > In this current series I don't do that as I wasn't totally convinced, > but it should be considered when reviewing. > > Hopefully this series gets enough interest where we can confidently > merge the final result after review helps improve it. > > I'll be travelling a good bit the next 2ish weeks, so expect little > response until my return. > > Thanks in advance for the help, > Andrew > > Signed-off-by: Andrew Halaney <ahalaney@xxxxxxxxxx> > --- > Changes in v2: > - Added review tags for original patch > - Added new patches to address all other memory barriers used > > - Link to v1: https://lore.kernel.org/r/20231208-ufs-reset-ensure-effect-before-delay-v1-1-8a0f82d7a09e@xxxxxxxxxx > > --- > Andrew Halaney (11): > scsi: ufs: qcom: Perform read back after writing reset bit > scsi: ufs: qcom: Perform read back after writing REG_UFS_SYS1CLK_1US > scsi: ufs: qcom: Perform read back after writing testbus config > scsi: ufs: qcom: Perform read back after writing unipro mode > scsi: ufs: qcom: Perform read back after writing CGC enable > scsi: ufs: cdns-pltfrm: Perform read back after writing HCLKDIV > scsi: ufs: core: Perform read back after writing UTP_TASK_REQ_LIST_BASE_H > scsi: ufs: core: Perform read back after disabling interrupts > scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL > scsi: ufs: core: Perform read back to commit doorbell > scsi: ufs: core: Perform read back before writing run/stop regs > > drivers/ufs/core/ufshcd.c | 10 +++++----- > drivers/ufs/host/cdns-pltfrm.c | 2 +- > drivers/ufs/host/ufs-qcom.c | 14 ++++++-------- > drivers/ufs/host/ufs-qcom.h | 12 ++++++------ > 4 files changed, 18 insertions(+), 20 deletions(-) > --- > base-commit: 20d857259d7d10cd0d5e8b60608455986167cfad > change-id: 20231208-ufs-reset-ensure-effect-before-delay-6e06899d5419 > > Best regards, > -- > Andrew Halaney <ahalaney@xxxxxxxxxx> >
